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1. Top results related to string (computer science)

   • string.IsNullOrEmpty(string) vs. string.IsNullOrWhiteSpace(string)

     Top Answer

     Answered Sep 29, 2017 · 368 votes

     The best practice is selecting the most appropriate one.

     .Net Framework 4.0 Beta 2 has a new IsNullOrWhiteSpace() method for strings which generalizes the IsNullOrEmpty() method to also include other white space besides empty string.

     The term “white space” includes all characters that are not visible on screen. For example, space, line break, tab and empty string are white space characters*.

     Reference : Here

     For performance, IsNullOrWhiteSpace is not ideal but is good. The method calls will result in a small performance penalty. Further, the IsWhiteSpace method itself has some indirections that can be removed if you are not using Unicode data. As always, premature optimization may be evil, but it is also fun.

     Reference : Here

     Check the source code (Reference Source .NET Framework 4.6.2)

     IsNullorEmpty

     [Pure]public static bool IsNullOrEmpty(String value) { return (value == null || value.Length == 0);}-

     IsNullOrWhiteSpace

     [Pure]public static bool IsNullOrWhiteSpace(String value) { if (value == null) return true;- for(int i = 0; i < value.Length; i++) { if(!Char.IsWhiteSpace(value[i])) return false; }- return true;}-

     Examples

     string nullString = null;string emptyString = "";string whitespaceString = " ";string nonEmptyString = "abc123";-bool result;-result = String.IsNullOrEmpty(nullString); // trueresult = String.IsNullOrEmpty(emptyString); // trueresult = String.IsNullOrEmpty(whitespaceString); // falseresult = String.IsNullOrEmpty(nonEmptyString); // false-result = String.IsNullOrWhiteSpace(nullString); // trueresult = String.IsNullOrWhiteSpace(emptyString); // trueresult = String.IsNullOrWhiteSpace(whitespaceString); // trueresult = String.IsNullOrWhiteSpace(nonEmptyString); // false-

     Other Answers

     Answered May 27, 2016 · 170 votes

     The differences in practice :

     string testString = "";Console.WriteLine(string.Format("IsNullOrEmpty : {0}", string.IsNullOrEmpty(testString)));Console.WriteLine(string.Format("IsNullOrWhiteSpace : {0}", string.IsNullOrWhiteSpace(testString)));Console.ReadKey();-Result :IsNullOrEmpty : TrueIsNullOrWhiteSpace : True-**************************************************************string testString = " MDS ";-IsNullOrEmpty : FalseIsNullOrWhiteSpace : False-**************************************************************string testString = " ";-IsNullOrEmpty : FalseIsNullOrWhiteSpace : True-**************************************************************string testString = string.Empty;-IsNullOrEmpty : TrueIsNullOrWhiteSpace : True-**************************************************************string testString = null;-IsNullOrEmpty : TrueIsNullOrWhiteSpace : True-

     Other Answers

     Answered Aug 07, 2011 · 39 votes

     They are different functions. You should decide for your situation what do you need.

     I don't consider using any of them as a bad practice. Most of the time IsNullOrEmpty() is enough. But you have the choice :)

     Check all answers on Stack Overflow

     1/5

   • String.Format vs "string" + "string" or StringBuilder?

     Top Answer

     Answered Dec 27, 2019 · 21 votes

     • Compiler will optimize as much string concat as it can, so for example strings that are just broken up for line break purposes can usually be optimized into a single string literal.
     • Concatenation with variables will get compiled into String.Concat
     • StringBuilder can be a lot faster if you're doing several (more than 10 or so I guess) "modifications" to a string but it carries some extra overhead because it allocates more space than you need in its buffer and resizes its internal buffer when it needs to.

     I personally use String.Format almost all of the time for two reasons:

     • It's a lot easier to maintain the format string than rearranging a bunch of variables.
     • String.Format takes a IFormatProvider which is passed to any IFormattable types embedded in the string (such as numeric) so that you get appropriate numeric formatting for the specified culture and overall just more control over how values are formatted.

     For example, since some cultures use a comma as a decimal point you would want to ensure with either StringBuilder or String.Format that you specify CultureInfo.InvariantCulture if you wanted to ensure that numbers were formatted the way you intend.

     Two more thing to note...

     • StringBuilder also has an AppendFormat function which gives you the flexibility of String.Format without requiring an unnecessary second buffer.
     • When using StringBuilder, make sure you don't defeat the purpose by concatenating parameters that you pass to Append. It's an easy one to miss.

     Check all answers on Stack Overflow

     2/5

   • string.contains() vs string.equals() or string == performance

     Top Answer

     Answered Jun 02, 2016 · 4 votes

     I agree with D Stanley (comment). You should use String.StartsWith()

     That said, I also don't know the inner working of each method either, but I can see your logic. However "String.Contains()" may still load the entire string before processing it, in which case the performance difference would be very small.

     As a final point, with a string length of only 45 characters, the performance difference should me extremely minute. I was shocked when I wrote a junky method to substitute characters and found that is processes ~10kb of text in a fraction of a blink of the eye. So unless you're doing some crazy handling else wise in your app, it shouldn't matter much.

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     3/5

   • String inside a string

     Top Answer

     Answered Apr 06, 2009 · 7 votes

     If you're working with URL parameters, it's probably safer to use urllib.urlencode:

     import urllib-BASE_URL = 'http://foobar.com/?%s'print BASE_URL % urllib.urlencode({ 'foo': 'bar', })

     Regarding the quotes: Why do you explicitly want them? Normally your HTTP-wrapper would handle all that for you.

     Regarding your 2nd question: If you absolutely also want to have the quotes in there, you still have to either escape them when appending the contained string, or (probably the safer way of doing it) would be using repr(...)

     lst = ['foo', 'bar', 'foo bar']lst2 = []-for l in lst: if ' ' in l: lst2.append(repr(l))

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     4/5

   • String Concatenation Vs String Builder Append

     Top Answer

     Answered Aug 15, 2015 · 15 votes

     Use StringBuilder. That's what it's for.

     Strings are immutable. String concatenation creates a new string, needing more memory, and is generally considered slow:

     string a = "John" + " " + "Saunders";-

     This creates a string "John ", then creates another string "John Saunders", then finally, assigns that to "a". The "John " is left for garbage collection.

     string a = "John";a += " ";a += "Saunders";

     This is about the same, as "John" is replaced by a new string "John ", which is replaced by a new string "John Saunders". The originals are left to be garbage collected.

     On the other hand, StringBuilder is designed to be appended, removed, etc.

     Example:

     StringBuilder sb = new StringBuilder();for (int i=0; i<n; i++){ sb.Length = 0; sb.Append(field1[i]); sb.Append(field2[i]); ... sb.Append(field30[i]); // Do something with sb.ToString();}

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     5/5

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2. en.wikipedia.org › wiki › String_(computer_science)String (computer science) - Wikipedia

   en.wikipedia.org › wiki › String_(computer_science)

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   String (computer science) Strings are typically made up of characters, and are often used to store human-readable data, such as words or sentences. In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length ...

3. www.geeksforgeeks.org › introduction-to-stringsData Structure and Algorithm Tutorials - GeeksforGeeks

   www.geeksforgeeks.org › introduction-to-strings

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   May 21, 2024 · Length is defined as the number of characters in a string is called the length of that string. Finding the Length of String. There are two ways to concatenate two strings: a) Length of string without using any inbuilt methods: Below is the algorithm for finding the length of two strings: 1. SET LEN = 0 AND I = 0.

4. www.geeksforgeeks.org › what-is-stringWhat is String - Definition & Meaning - GeeksforGeeks

   www.geeksforgeeks.org › what-is-string

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   Jan 19, 2024 · Applications of String: Strings are widely used in computer science and have many applications in various fields, some of which are: Text Processing: Strings are used to represent and manipulate text data, such as in text editors, word processors, and other applications that deal with text.

5. People also ask

   What is a string in computer programming?

   • Strings are typically made up of characters, and are often used to store human-readable data, such as words or sentences. In computer programming, a string is traditionally a sequence of characters, either as a literal constant or as some kind of variable.

   String (computer science) - Wikipedia

   en.wikipedia.org/wiki/String_(computer_science)

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   How are strings used in Computer Science?

   • Strings are widely used in computer science and have many applications in various fields, some of which are: Text Processing: Strings are used to represent and manipulate text data, such as in text editors, word processors, and other applications that deal with text.

   What is String - Definition & Meaning - GeeksforGeeks

   www.geeksforgeeks.org/what-is-string/

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   Is a string a data type?

   • The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). A string is generally considered as a data type and is often implemented as an array data structure of bytes (or words) that stores a sequence of elements, typically characters, using some character encoding.

   String (computer science) - Wikipedia

   en.wikipedia.org/wiki/String_(computer_science)

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   What is a string in C?

   • In C, a string can be referred to either using a character pointer or as a character array. When strings are declared as character arrays, they are stored like other types of arrays in C.

   Introduction to Strings – Data Structure and Algorithm Tutorials

   www.geeksforgeeks.org/introduction-to-strings-data-structure-and-algorithm-tutorials/

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6. www.geeksforgeeks.org › string-data-structureString in Data Structure - GeeksforGeeks

   www.geeksforgeeks.org › string-data-structure

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   • String Data Type. In most programming languages, strings are treated as a distinct data type. This means that strings have their own set of operations and properties.
   • String Operations. Strings support a wide range of operations, including concatenation, substring extraction, length calculation, and more. These operations allow developers to manipulate and process string data efficiently.
   • Introduction to Strings: Introduction to Strings – Data Structure and Algorithm Tutorials. Applications, Advantages and Disadvantages of String. Storage for Strings in C.
   • String in different language: Strings in C. String Class in C++ String Class in Java. Python String. C# | String. JavaScript String. PHP | Strings.

7. www.khanacademy.org › computing › ap-computerProgramming with strings | AP CSP (article) | Khan Academy

   www.khanacademy.org › computing › ap-computer

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   Here's what happens on that first line: JavaScript looks for a variable named GrayFox. If it could actually find one, it would set the player variable equal to the value of the GrayFox variable. Since it doesn't find one, it errors instead. If you want it to store the literal string, you must surround it in quotes.

   • How do you store quotation marks in strings if they're part of the syntax, and how are line breaks m...

     In JavaScript, the two main ways to store quote marks inside strings is to either "escape" the quotes with a backslash, or to use the opposite-styl...
   • Is possible to get an overflow error in a string variable? I mean like overflow error in number vari...

     Not like numbers precisely. With numbers you have space and an encoding: For example, say you have 4 bits and you only encode positive numbers in b...
   • What is the difference between Javascript and Java?

     Java and Javascript are different programming languages; each one has its own purpose. Javascript is used heavily when creating websites while Java...
   • Is there a reason you don't have to declare a variable in Python and you have to include the data ty...

     Yes, there is a fundamental difference in the way Python and Java handle variables and their data types. Python is a dynamically typed language, wh...
   • Hello, I have have just started backusing khan academy,such a great app to learn to code and all the...

     This pseudocode is the pseudocode style that is used by the AP CSP exam and it does *not* use semi-colons. If you aren't taking the AP CSP exam, I'...
   • Is there a way to execute code that is in a string? Like: "function myFunction () {}" or "if(a){prin...

     Yes, you can use the eval function to run code stored as a string in JavaScript (e.g. `x = eval("3 + 5")`). However, YOU SHOULD NOT USE THIS FUNCTI...

8. www.khanacademy.org › computing › ap-computerString operations in programs | AP CSP (article) | Khan Academy

   www.khanacademy.org › computing › ap-computer

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   Depending on what you're trying to do in your program, you may want to modify strings in other ways. Here's a short list of common string operations across languages: Operation. JavaScript example. Finding the position of a character in a string. "hello".indexOf ("e") Converting a string to all lowercase or uppercase.

9. eng.libretexts.org › Bookshelves › Computer_Science7.1: Strings - Engineering LibreTexts

   eng.libretexts.org › Bookshelves › Computer_Science

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   Overview. A string is traditionally a sequence of characters, either as a literal constant or as some kind of variable. The latter may allow its elements to be mutated and the length changed, or it may be fixed (after creation). A string is generally considered a data type and is often implemented as an array data structure of bytes (or words ...